Process of coating paper



Aug. 8, 1933. P. J. MASSEY 1,921,363

PROCESS OF COATING PAPER Filed May 29, 1930 2 Sheets-Sheet 1 Aug. 8, 1933. P. J. MASSEY 1,921,368

PROCESS OF COATING PAPER Filed May 29, 1950 2 Sheets-Sheet 2 R c O o N 6 m e 6 k f e 0 b v g;

fi 7/6272 for.

Patented Aug. 8, 1933 v a 1 UN T S ATES PA ENT FFICE la /[1,921,368 v "i Pnoonss F COATING PAPER." j

H Peter J. Massey, Forest, Ill. v Application May'29, 1930." Serial l\lo.;457 ,116 11 Claims. (01. 91148) This invention relates to a method of coating to coating unit .11 wherein a suitable coating mapaper with a suitable coating substance to pro-. ,terial may be applied to the continuously} moving duce thereon a coated surface having desirable, web' '2 to produce a. .paper' having a coated surcharacteristics for printingand refers morep'ar- ,face suitable for purposes of printing. I

' ticularly to the coating of paper as it passes The coating'u'nit 11 may comprise a -foimtain 60 from a portion of the driers of apaper machine, ortrough12 adapted to. contain a solution or sus- X as a step in a continuous process of manufacture pension of coating material 1 3. The coating maof coated paper. f te'rial 13 may be introduced to the container or This application constitutes a continuation in fountain 12 through line 14,-controlledbyflvalve part of my earlier application, Serial No. 450,614, 15. The material 13. may be maintained in .foun- 65 filed May 8, 1930. v t tain 12 under superatmospheric or, desired, The utility; objects and advantages of the in-, may be maintained at atmospheric, pressure and vention will be apparent from the accompanying may be transferred therefrom by gravity.

, drawings and following detail description.. The material 13may comprise a solution or sus- In the drawings, Figl 1 is a diagrammatic side pension of suitable coating substances such as, 70 elevational view illustrating. a portion of the apfor example, size, glue, gelatin, casein, starch, paratus suitable for carrying out my invention. clay, calcium sulphate, resin, oilsand/or var- Fig. 1 is 'adiagrammatic elevational view of the nishes carried and/ or dissolved in a vehicle and/ or remaining portion of such apparatus. diluent of water or oil. Ifhe proportion of liquid Referring in detail to the drawings, 1 indi-, to soluble material may range in the approximate 75 cates a pair of smoothing rolls interposed between vicinity of 50%, more or less. It is to be under a paper machine (not shown), which may comstood, of course, that the hereinbefore mentioned prise usual beating units, felting units, press rolls examples and proportions are given merely for and the like, andadrying unit indicated generalpurposes of example and are not intended to 1y at 3. The drying unit 3 may take the form I serve in any way asfa limitation upon my inven- 8 of a conventional multi-tier drier having a plution, 'since any of the well known materials for- 'rality of upper drying rolls 4 disposed above a coating paper may be used and the exact proporlower tier of drying rolls 5 staggered in a vertitions of solvents and/or vehicles to the binders cal plane from the upper rolls. Guide rolls 6 may and coating substances proper may be determined be interposed between each of the rolls 4 comprisby the quality or character of coating to be pro- 85 mg the upper tier of driers and are adapted to duced and type of paper being coated. H

guide a continuous dry felt 7 which may be adapt- A roll 16 may be journalled in such a manner ed to passin turn over the upper surface of the as to rotate adjacent fountain 12 and may be drying rolls 4 and around the lower surface of the adapted to contact the material 13 and'thus have guide roll 6. The felt 7 may take the form of an deposited a film of said material on its surface. 90 endless unit, and upon passing over the upper The thickness of the film may be determined by series of drying and guide rolls 4 and 6, respecproper regulation of a conventional doctor blade tively, may return over a suitable arrangement of 17 operatively associated with the fountain and guide rolls 8, over tightening unit 9, and if deroll 16. Roll 16 may be constructed of metal or sired may pass around a plurality-of pony driers some like materiah in 10 and thence back to the wet end of drying unit 3. A roll 18 may be journalled at one end of a A similar felt 7' may pass around the lower swinging arm 19, the other end of which may be surfaces of each of the driers 5 and over the uppivoted at ,20. The surface of roll I 18 may be per surfaces of guide rolls 6 suitably interposed constructed of rubber, or rubber, composition, or between each of the driers 5. Felt 7 may return some other material having relatively. pliable over guide rolls 8, over tightening unit9', and if v properties. Arm 19 may be operatiyely connected desired, over a plurality of pony driers 10 and and synchronized with the remaining elements of back to the wet end of drying unit 3. The web the apparatus to be hereinafter described in such 2 upon passing from smoothing unit 1 may be a manner that atone period of operation roll 18 carried over the lower surface of..the initial drycontacts roll 16, which actiontransfers a portion ing roll 5 of the lower tier, and thence may pass. of the film on the surface of roll 16 to the surface J over the upper surface of the initial drying roll 4, 'of'; roll 18. At a subsequent period '3 of the cycle of the upper tier and so on through the entire roll 18 is swung into contact withthe surface of span of driers. a vibrating distributing drum 21, thereby trans- The web 2 upon leaving drying unit 3 may pass mitting its surface film tothe surface of drum 21.

Said drum may be constructed of metal or other like material, the entire roll being adapted to vibrate or oscillate longitudinally, thereby tending to obtain a longitudinal distribution of said iilm upon its surface.

A rubber or compositioned-surface transfer roll 22 may contact roll 21 and hence transfer the film from roll 21 to its own surface. Transfer roll 22 may in turn contact vibrating distributing drum 23, which may, if desired, be constructed to vibrate or oscillate longitudinally, thereby further tending to establish a uniformly distributed film upon its surface. The drum 23 may be constructed of a material similar to that comprising drum 21.

A pair of transversely oscillating distributing drums 24 and 25 may be rotatably mounted adjacent drum 23 and may have their respective surfaces subjected to the film upon drum 23 through the agency of the pliable surfaced rolls 26 and 27, respectively. In this manner an extremely well worked film of coating material 13 may be established upon the surfaces of rolls 24 and 25, respectively.

By means of a plurality of pliable rolls 28 the film upon the surfaces of drums 24 and 25 may be transferred to the surface of coating roll 29. The surface 30 of roll 29 may be constructed of a relatively pliable material, such as rubber or rubber composition.

The coating roll 29 may comprise a portion of the coating unit proper which may consist of a base 31 upon which may be mounted upstanding guides 32. The lower coating roll 29', similar in construction to roll 29, may be mounted between the lower portion of guides 32 as at 33. The roll 29 may be mounted between guides 32 immediately above roll 29', the respective surfaces thereof being normally in contact. The contacting pressure of roll 29 upon roll 29'- may be varied by the obvious manipulation of the system of linkages shown generally at 34.

It is to be understood, of course, that the various instrumentalities described in connection with coating unit 11 merely constitute one arrangement with which my invention may be carried out. Many other possible arrangements will suggest themselves to anyone skilled in the art, and I wish it to be understood that the invention is not in any way limited to the particular arrangement shown, which happens merely to be a form chosen to illustrate the invention.

Web 2 upon passing from drying unit 3 is carried forwardly between coating rolls 29 and 29' wherein a uniformly distributed film of coating material from the surfaces of said rolls is simultaneously transferred and compacted upon both surfaces of web 2. The web may then pass over a suitable guide roll 35 to an auxiliary drying unit 36, which may comprise conventional upper and lower drying rolls 4 and 5, respectively. Inasmuch as coating material 13 after passing over the series of transfer rolls described in connection with the coating unit loses a large proportion of its liquid content, principally by evaporation, the web 2 upon issuing from said coating unit needs a relatively short subsequent drying period, and hence the number of drying rolls 4 and 5 comprising unit 36 may be reduced to a minimum, and such auxiliary felt drying equipment as the pony driers 10 and 10' may be eliminated if desired. If desired, a drier felt 7 may be used in the final drying unit 36, or the felt may be entirely eliminated, or the first two or three rolls 4 and 5 of the unit 36 may be run bare and a drier felt used upon the remainder of the rolls.

The web 2 upon issuing from drying unit 36 may pass to a stack of calender rolls 37 wherein the paper may be properly finished. Or, if desired, said web may be passed through both calender unit 37 and an additional calender unit 38. Upon issuing from the final calender stack 38 the paper may be reeled in any suitable manner (not shown). It is to be understood, of course, that any type calender or calenders may be utilized:

In passing through the coating unit 11 the coating material may be applied to one or both the rolls 29 and 29' and from the latter transferred to one or both surfaces of the web 2 in a uniform smooth film. Due to the efllcient action of thevarious rolls constituting the coating unit 11 a solution or suspension of coating material may be used having a relatively low liquid content. As a result, due to the evaporation which takes place during the progress of the coating material through the rolls, the coating material applied to the web is in a relatively concentrated condition. Hence, the period of subsequent drying is reduced to a minimum and the coating material upon the surface, or surfaces, of the web needs no further working.

By suitably manipulating the doctor blade 17 and controlling the pressure of roll 29 upon roll 29' coatings may be applied to the web ranging in dry weight from approximately .05 to 5 pounds per one hundred square inches of paper, more or less.

As can be readily seen, the system of rolls appurtenant to coating roll 29' and designated by primed reference numerals is similar in all respects to the series described in connection with roll 29 and needs no further elaboration.

By properly controlling the feed of coating material from the troughs 12 and 12' to rolls l6 and 16', respectively, and by suitably gauging the contacting pressure of the coating rolls 29 and.

29', a smooth film of uniform thickness of preworked coating material may be compacted upon said paper at any of the various speeds at which the paper machine proper may operate or, more strictly speaking, at any speed at which the web 2 may travel, it being possible to properly coat a web of paper moving at a speed of twelve hundred feet per minute, or higher, as uniformly and as well as a web moving appreciably slower.

By the term worked and/or pre-worked as used in the specification and claims is meant the step of reducing the coating material to the proper consistency for application to the web, as well as the step of progressively more uniformly distributing the film of material as the same is passed from roll to roll in the coating unit so that no further smoothing, scraping or brushing is necessary to produce a completely finished coated paper.

In utilizing my invention, as a step in a continuous process of manufacture of coated paper, the web after being properly felted and pressed, may be passed to a plurality of drying rolls, wherein the web is preferably thoroughly dried before passing to the coating unit. It is to be understood, of course, that the number of drying rolls immediately preceding the coating unit may be 'less than that sufficient to thoroughly dry the web, since the moisture content of the coating material when applied to the web is comparatively small and is not suflicient to detrimentally affect the paper in passing through the coating vlow the coating step, and what virtually occurs,

is that the final driers of the paper machine are divided into two sections and thecoating unit interposed therebetween.

It is apparent that herein is provided a method of efiiciently continuously applying a coating to a web of paper as the same passes through the driers of a paper machine; a coating process which may accommodateitself to any of the various speeds now used in the manufacture of paper. A paper making machine when utilizing my invention presents not merely a machine and method of making paper, but broadly comprises a machine and method for making coated paper.

By the use of the term coated paper suitable for printing purposes I intendto define the application of a coating substance to the paper of a character conditioning the paper for printing thereon.

I claim as my invention:

1. A continuous progressive method of producing a uniformly coated fibrous sheet suitable for printing purposes, which comprises the following steps: forming a continuous wet fibrous web, drying said web under elevated temperature, bringing said web into contact with moving surfaces carrying a uniformly distributed film of coating material, simultaneously transferring said material as a pre-worked smooth finished coating to opposed sides of the web under pressure and drying said coated web, said pro-Worked film being of relatively concentrated condition whereby it will not detrimentally affect the fibrous web.

2. A continuous progressive method of producing a uniformly coated fibrous sheet suitable for printing purposes, which comprises the following steps: forming a continuous wet fibrous web, drying said web under elevated temperature, bringing said web into contact with a moving surface carrying a uniformly distributed film of coating material previously transferred to said moving surface through a plurality of contacting moving surfaces whereby the film is pre-worked and substantially dehydrated, transferring said material as a continuous finished coatingto said web under pressure and drying said coated web, the concentrated condition of the pro-worked film being such as not to detrimentally affect the web.

3. A continuous progressive method of producing a uniformly coated fibrous sheet suitable for printing purposes, which comprises the following steps: forming a continuous Wet fibrous web, drying said web under elevated temperature, treating a coating mixture, comprising a coating substance and a carrier, to eliminate a sufficient portion of the carrier to render the mixture suitable for coating the fibrous web without detrimentally affecting the web, while simultaneously reducing the mixture to a desirable physical condition to smoothly coat the web thereafter coating the web with said reduced mixture and subsequently and without further working of the coating drying the coated web.

4. A continuous progressive method of producing a uniformly coated fibrous sheet suitable for printing purposes, which comprises the following steps: forming a continuous wet fibrous web, drying said web under elevated temperature, depositing a mixture comprising coating material and a liquid carrier on a moving surface, the viscosity of said mixture being below that desired for coating, transferring said mixture to a second moving surface, working said mixture to cause it to spread and form a uniform film on said second moving surface while simultaneously increasing the viscosity of the mixture, continuing such.

treatment until the mixture has-reached the desired viscosity and is in the form of a uniform film having insufficient water to streak and detri-- mentally affect the .web, then transferring said uniform film of desired viscosity to the fibrous web, simultaneously compacting the same thereon in the formof a finished coating and subsequently 'drying said coated web.

5. A continuous progressive method of producing a uniformly coatedfibrous sheet suitable for ing said web under elevated temperature, passing said web between opposed rotating surfaces carrying preformed films of uniform thickness in which the coating material is uniformly distributed, transferring said preformed films simultaneously to opposite surfaces of said continuously advancing web under the pressure of said opposed rotating surfaces as finished coatings the said pre-worked films being substantially dehydrated whereby there is insufficient water to detrimentally streak and affect the web.

6. The method of making coated paper suitable for printing purposes, which comprises the steps of treating the coating material to increase its viscosity by eliminating substantial quantities of its liquid content and render it relatively plastic, advancing a web of fibrous material and transferring the treated material as a viscous and smooth film to the entire surface of the web under pressure whereby to obtain a final coated product suitable for printing purposes.

7. The process of making coated paper for printing purposes, which comprises continuously advancing a web of paper, subjecting a coating mixture to mechanical working action to smooth it and eliminate portions of the liquid contained therein and transferring said mixture as a mechanical pre-worked film to the advancing web under pressure, the liquid content of the film being insufiicient to detrimentally streak the web uponwhich it is transferred.

8. The process of making coated paper suitable for printing purposes, which comprises the steps of treating a coating mixture, comprises a coating substance and a liquid carrier, to eliminate a sufficient portion of the carrier to render the mixture suitable for coating the paper without streaking the same while simultaneously reducing the mixture to a desirable physical condition to smoothly coat the paper, advancing a web of paper continuously and depositing said mixture upon the surface of the advancing web as a smooth finished coating therefor.

9. A continuous process of making coated paper suitable for printing purposes, which comprises the following steps: depositing a mixture comprising coating material and a liquid carrier upon a moving surface, the viscosity of said mixture being below that desired for coating, transferring said mixture to a second moving surface, working said mixture to cause it to spread and form a uniform film on said second moving surface while simultaneously increasing the viscosity of the mixture, continuing such treatment until the mixture has reached a viscosity such as will not detrimentally streak or affect the web and isin the form of a uniform film and then transferring said uniform film to a web of paper and simultaneously compacting the film thereon.

10. A continuous process of making coated paper suitable for printing purposes, which comprises the steps of depositing a mixture including coating material, a liquid carrier upon a rotating surface, the viscosity of said mixture being below that desired for coating, transferring said mixture to a second rotating surface, working said mixture to cause itto spread and form a uniform film of said second rotating surface while simultaneously increasing the viscosity of the mixture, continuing such treatment until the mixture has reached the desired viscosity such as will not detrimentally affect the web, and is in the form I of a uniform film, transferring said uniform film in its viscous state to a web of paper simultaneously compacting the same thereon, in the form of an unbroken, smooth coating, the viscous condition of the fihn minimizing the drying action required for the coated product.

11. The herein'described process for making 

